Microfabrication by lithography using photoresists has been carried out in production of semiconductor devices. The microfabrication is a processing method including forming the thin film of a photoresist on a semiconductor substrate such as a silicon wafer, irradiating the formed thin film with active light such as ultraviolet rays through a mask pattern in which a semiconductor device pattern is drawn, developing the irradiated thin film, and etching the substrate using the obtained photoresist pattern as a protecting film, thereby forming fine unevenness corresponding to the pattern. In recent years, however, semiconductor devices have been further integrated, and the active light to be used has tended to have a shorter wavelength from a KrF excimer laser (248 nm) to an ArF excimer laser (193 nm). This has raised serious problems of the effects of the reflection of active light from the semiconductor substrate.
As an underlayer film between the semiconductor substrate and the photoresist, a film known as a hard mask containing metal elements such as silicon or titanium has been used. In this case, the resist and the hard mask have a large difference in their constituent components and thus the rate of removal by dry etching significantly depends on the kind of gas used for the dry etching. The hard mask can be removed by the dry etching without significant reduction in the film thickness of the photoresist by appropriately selecting the kind of gas. As described above, in order to achieve various effects such as antireflection effect, a resist underlayer film has been disposed between the semiconductor substrate and the photoresist in the production of semiconductor devices in recent years. Studies on the composition for the resist underlayer film have been carried out up to now and development of new materials for the resist underlayer film is desired from the viewpoint of diversity of required properties and the like.
For example, a resist underlayer film containing a polysiloxane using a silane having a sulfone structure has been developed (refer to Patent Document 1).
A resist underlayer film containing a polysiloxane using a silane having a sulfonamide structure has also been developed (refer to Patent Document 2).
A resist underlayer film containing a polysiloxane using a silane having a sulfone structure and an amine structure has also been developed (refer to Patent Document 3).